My guess is 28nm is already an aging node, and by the time any fab based on it becomes operational, the technology will be even more obsolete. It’s hard to predict what the market will look like then. You can't expect a private company to pour billions into a dicey market.
This is a case where free-market capitalism doesn’t work. You really want a government pitching tens of billions of dollars to get to the cutting edge fast, not expecting companies to foot the bill and just dangle a few incentives.
Frankly, for India, the entire semiconductor ambition feels like putting the cart before the horse. It won't create jobs, most value will be captured by fab owners. The smarter approach would be top-down: start with component assembly, then build up CNC machining, injection molding, and other foundational industries that can fill in the gap for components. Only after that should we talk about high-value semiconductor manufacturing.
India lacks even the most basic manufacturing. We import stuff like lighters, toys, and basic electronics. Why do we want to make the giant leap to semiconductors?
Unfortunately, Indian policymakers are more interested in optics than in long-term industrial planning.